Sounds like you handled the situation well. I would caution you about letting strange men touch your dick if you don't want to go further. No means no, but there is some implied consent there, and I've known some straight boys unable to say no once their dick was being played with. I think you've demonstrated that you don't need to beat the crap out of creepers (or other gay men) in the showers, that I firm "no, but thank you" is sufficient. Good luck with your new admirer.